netfilter: ctnetlink: use dump structure instead of raw args

netlink_dump structure has a union of 'long args[6]' and a context
buffer as scratch space.

Convert ctnetlink to use a structure, its easier to read than the
raw 'args' usage which comes with no type checks and no readable names.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index ac438370f94a9240bf1242bf54e36a66fdb6970c..3d9f9ee50294693e3b33b84d0727ad2433f5a470 100644 (file)
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -58,6 +58,12 @@
 
 MODULE_LICENSE("GPL");
 
+struct ctnetlink_list_dump_ctx {
+       struct nf_conn *last;
+       unsigned int cpu;
+       bool done;
+};
+
 static int ctnetlink_dump_tuples_proto(struct sk_buff *skb,
                                const struct nf_conntrack_tuple *tuple,
                                const struct nf_conntrack_l4proto *l4proto)
@@ -1694,14 +1700,18 @@ static int ctnetlink_get_conntrack(struct sk_buff *skb,
 
 static int ctnetlink_done_list(struct netlink_callback *cb)
 {
-       if (cb->args[1])
-               nf_ct_put((struct nf_conn *)cb->args[1]);
+       struct ctnetlink_list_dump_ctx *ctx = (void *)cb->ctx;
+
+       if (ctx->last)
+               nf_ct_put(ctx->last);
+
        return 0;
 }
 
 static int
 ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying)
 {
+       struct ctnetlink_list_dump_ctx *ctx = (void *)cb->ctx;
        struct nf_conn *ct, *last;
        struct nf_conntrack_tuple_hash *h;
        struct hlist_nulls_node *n;
@@ -1712,12 +1722,12 @@ ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying
        struct hlist_nulls_head *list;
        struct net *net = sock_net(skb->sk);
 
-       if (cb->args[2])
+       if (ctx->done)
                return 0;
 
-       last = (struct nf_conn *)cb->args[1];
+       last = ctx->last;
 
-       for (cpu = cb->args[0]; cpu < nr_cpu_ids; cpu++) {
+       for (cpu = ctx->cpu; cpu < nr_cpu_ids; cpu++) {
                struct ct_pcpu *pcpu;
 
                if (!cpu_possible(cpu))
@@ -1731,10 +1741,10 @@ restart:
                        ct = nf_ct_tuplehash_to_ctrack(h);
                        if (l3proto && nf_ct_l3num(ct) != l3proto)
                                continue;
-                       if (cb->args[1]) {
+                       if (ctx->last) {
                                if (ct != last)
                                        continue;
-                               cb->args[1] = 0;
+                               ctx->last = NULL;
                        }
 
                        /* We can't dump extension info for the unconfirmed
@@ -1751,19 +1761,19 @@ restart:
                        if (res < 0) {
                                if (!refcount_inc_not_zero(&ct->ct_general.use))
                                        continue;
-                               cb->args[0] = cpu;
-                               cb->args[1] = (unsigned long)ct;
+                               ctx->cpu = cpu;
+                               ctx->last = ct;
                                spin_unlock_bh(&pcpu->lock);
                                goto out;
                        }
                }
-               if (cb->args[1]) {
-                       cb->args[1] = 0;
+               if (ctx->last) {
+                       ctx->last = NULL;
                        goto restart;
                }
                spin_unlock_bh(&pcpu->lock);
        }
-       cb->args[2] = 1;
+       ctx->done = true;
 out:
        if (last)
                nf_ct_put(last);
@@ -3877,6 +3887,8 @@ static int __init ctnetlink_init(void)
 {
        int ret;
 
+       BUILD_BUG_ON(sizeof(struct ctnetlink_list_dump_ctx) > sizeof_field(struct netlink_callback, ctx));
+
        ret = nfnetlink_subsys_register(&ctnl_subsys);
        if (ret < 0) {
                pr_err("ctnetlink_init: cannot register with nfnetlink.\n");